This invention relates to a plunger operating mechanism for operating a parison plunger in an I.S. type glassware forming machine.
In the production of glass containers by the press and blow method on the well known I.S. type machine, a gob of glass is provided to a parison mold which is then closed, and the glass is pressed into the required shape of a parison by a plunger moving upwardly into the mold, a lower portion of the glass being forced into a neck ring of the mold. The plunger is then withdrawn and the parison is carried by the neck ring away from the parison molding station and is transferred to a blow mold station where it is blown to the required shape. A typical plunger operating mechanism is shown in U.S. Pat. No. 4,272,273. This mechanism is pneumatically operated and comprises a lower cylinder member having a vertical cylindrical bore closed at its lower end by an integral base portion, in which bore is mounted a piston head on a piston rod. The upper, free, end of the piston rod supports a plunger. Secured in the base portion of the cylinder member is a rod guide in the form of a hollow tube, which serves to guide the piston rod and also to supply cooling air to the plunger mechanism. The upper end of the cylindrical bore is closed by a separate upper casing. Sandwiched between the lower cylinder and the upper casing is a cylinder sealing portion through which the piston rod passes. The upper casing, which receives a plunger guiding and positioning mechanism, is clamped to the lower cylinder with suitable fasteners. This construction, comprising the lower cylinder member and the upper casing secured to it, is expensive.
It is accordingly an object of the present invention to provide a plunger operating mechanism, which is more economical.
Other objects and advantages of the present invention will become apparent from the following portion of this specification and from the accompanying drawings, which illustrate in accordance with the mandate of the patent statutes a presently preferred embodiment incorporating the principles of the invention.